The field of dental hygiene has changed significantly over the past several years. More hygienists are staying in the field longer, working more hours and performing more physically difficult procedures. These new work hazards, along with the necessary hazard of placing the body in fixed or awkward work positions, have caused an increase of musculoskeletal stress and injuries in the workplace.
Musculoskeletal pain in the neck and shoulders are reported in people who work in fixed awkward positions and/or have prolonged exposure to static or repetitive arm movement. The dental hygiene professional is exposed to all of these hazards, and the therefore dental hygienists are a group severely affected by musculoskeletal pain. In recent years, ergonomic studies have shown that musculoskeletal pain in the neck and shoulders is a major cause of work absence and workman's compensation claims. This pain can also interfere with patient care by diminishing the speed and quality of work. As more dental hygienists develop musculoskeletal problems, the physical, emotional and financial costs are becoming overwhelming.
The exact mechanism underlying work-related muscular pain syndrome is not yet fully understood. According to Swedish studies, the possible mechanisms may be related to high intramuscular pressures. This is true especially in muscles incased in narrow compartments (i.e. supra spinus muscle) or disturbances in the sympathetic regulation of muscular microcirculation (trapezium muscle). Other possible mechanisms include excessive load of small, low threshold motor units due to the lack of pauses or pain induced by vicious feedback loops which increases muscle tension leading to more pain. In work related muscle pain there are also reports of microscopic changes in type-1 (slow, fatigue resistant) muscle fibers.
The dental hygienist works with his/her arms in a position of abduction. The work may be classified as sitting or standing work within a limited space with time restraints. There are few pauses during treatment sessions and limited movements for extended periods of time. This may result in static muscle contractions (little or no change in extension or flexion of the muscle fibers), thus placing a prolonged musculoskeletal stress on the dental hygienist. These factors can contribute to muscular pain syndrome.
Considerable effort has been expended to prevent or to alleviate the muscular pain syndrome. In 1993, Tommy Oberg, MD, Phd, director and professional ergonomist in the Department of Biomechanics and Orthopedic Technology at the University College of Health Sciences, in Sweden, developed two ergonomic devices for the dental professional. He developed an operator chair with an attached armrest, as well as an attachment on the patient's headrest, to attempt to remedy the described work hazards of the dental hygiene profession However, Dr. Oberg's invention did not solve all the problems leading to muscular pain syndrome in dental hygienists. It did not provide the necessary support for the hygienist while positioned over the patient. Furthermore, the device of Dr. Oberg's invention is large and both devices are located in areas that would hamper the freedom of movement of the operator as well as being inconvenient for the patient. Dr. Oberg's invention is also cumbersome, expensive, and difficult to install. Finally, Dr. Oberg's devices are permanently fixed in one location. It does not allow for adjustment to cover all possible angles of the dental practitioner's work.